The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to form super-junction field effect devices. These devices typically had alternating P and N columns formed in a substrate with the active area of the field effect device overlying the alternating P and N columns. One example of such a super-junction field effect device was disclosed in U.S. Pat. No. 6,274,904 issued to Jeno Tihanyl et al on Aug. 14, 2001, which is hereby incorporated herein by reference. One problem with these prior structures was the manufacturing cost. Typically, the alternating P and N columns were formed by growing multiple thin N-type epitaxial layers and implanting each epitaxial layer with boron to form the P regions prior to growing the next epitaxial layer. Growing the multiple epitaxial layers required many processing steps, and aligning the P and N columns within each epitaxial layer was difficult. Implanting each epitaxial layer required precise alignment between the layers which also increased cost and reduced manufacturing yields.
In order to form the multiple P and N columns, a highly doped epitaxial layer was required. Sometimes the doping was greater than 5E15 atoms/cm2. Because of the highly doped epitaxial layer, these alternating P and N columns were also required in the termination region of the field effect device. The complex termination region further increased the costs.
Accordingly, it is desirable to have a super-junction field effect device that does not require growing multiple epitaxial layers, that does not require a highly doped epitaxial layer, that has a simple termination structure, and that has reduced manufacturing cost.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. For clarity of the drawings, doped regions of device structures are illustrated as having generally straight line edges and precise angular corners. However, those skilled in the art understand that due to the diffusion and activation of dopants the edges of doped regions are generally not straight lines and the corners are not precise angles.